Chin strap buckle



FIG. 1 is a perspective view of a chin strap buckle showing my new design;

FIG. 2 is a top plan view of a chin strap buckle in accordance with the claimed design;

FIG. 3 is an end plan view thereof;

FIG. 4 is a side elevational view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top perspective view thereof; and,

FIG. 7 is a bottom perspective view thereof.

The broken lines in the FIG. 1 are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a chin strap buckle, as shown and described. 